Telephone-exchange system.



No. 772,833. y PATENTED 00T. 1a, V1904.

C. E. SCRIBNBR.

'IBLEPHONE EXCHANGE SYSTEM.

APPLICATION FILED oo'I.21, 1869.

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UNITED vSTATESY Patented October 18, 1904.

IPATENT OFFICE.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE wEST- ERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

`TELEPl-IONE-E'x'oi-l'ANeE SYSTEM.

SPECIFICATION forming part of Letters `Patent No. 772,833, dated October 18, 1904. l i Application filed October 21, 1899. `Serial No. 734,355. (No-model.)

To all' whom it m/ru/ concern:

Be it known that I, CHARLES E. SCRIBNER, a citizen of the United States, residing at Chicago, in the county of Cook and State oi' Illinois, have invented a certain new and useful Improvement in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

My invention applies to telephone-exchange systems in which call-signals are transmitted to the operator at the switchboard fromthe substations automatically in the use of the substation-telephones, the switchboard-signals being subsidiary Signaling instruments controlled through the medium of relays responsive to currents in the lines. In switchboards .provided with this type of signals hitherto constructed the signal-controlling relay has been placed in a branch or bridge of the line-circuit, together with a source oi' current, and the plug-circuits for uniting lines have been interrupted as to continuous currents by interposed repeating-coils in order that the relays might be permitted to respond independently each to current in its own line only. This arrangement has been open to the objection that the relay was shunted by the repeating-coil to the extent under some circumstances of rendering it inoperative. My present, improvement upon this system consists in constructing the relay inthe line-circuit to serve itself as a repeating-coil and in adapting the circuits withinthe switchboard to this change in the apparatus. By this reorganization oi' the system the entire signaling-current through the line is caused to traverse the line-relays under all circumstances, and the independent working of the relays is obtained without the use of Supplemental apparatus vin the vplu, ,rcircuit, Sothat both an Aimproved mode of operation and an economy of apparatus are attained. 4The conductive'independence ofthe portion of the line extending to the substation from the portion leading into theiswitchboard has the further advantage that *no-'variationof the current in the line is prol duced in the act of switching the line, the switch connections being independent and local, whereby annoying clicks and disturbi ances in the telephones of calling Subscribers are avoided. This improved system, then, involves a repeating-coil provided with an armature having switch-contacts for controlling the -circuitsthrough the subsidiary signals. The telephone-line is closed-through one helix oi' this repeating-coil, a battery or other source of current being looped into the circuit, preferably at the middle oi' the resistance in the repeating-coil helix. The other winding of the repeating-coil is led to the spring-jacks or connection sockets in the Switchboard. When a connection is completed between two lines by means oi' a plug-circuit, the two lines are united `inductively through the medium of their respective repeating-coils, the circuit through the switchboard being a local circuit with no Conductive connection with the linecircuits and free from battery connections. Thus each of the line-helices of the repeatingcoils controls its own armature in response to currents through its own line determined by the use or disuse of the corresponding telephone.

My improvement is shownin the accompanying drawing in connection with a system of subsidiary signals which forms the subject of a prior patent, No. 669,708, dated March I2, 190i.

In the drawing, vtwo telephone-lines are represented terminating in a telephone-switchboard. Line conductors 1 and y2 of the line are permanently united at the su bstation through a conductor 3, which includes a polarized signal-bell t and which is interrupted as to unvarying currents by the condenser a interposed init. A second bridge, 4, of the line includes the usual receiving-telephone a2 and transmitting telephone a3 and is normally open at the switch-contacts ofa telephoneswitch c. The telephones may bel provided with any of the well-known means of supplying current for the operation of the transmitting instrument.

At the central station the line conductors 1 and 2 are united through'the winding of the repeating-coil b andthrough the battery c. In other words, the line conductor 1 may be considered as extending through one halt' the winding Z/ to one pole of battery c and the line conductor 2 through the other halt' ot' the same winding to the other pole ot' battery c. This battery may be common to the different teleplione-lines of the exchange. The other helix, b2, of the repeating-coil is connected by wires 5 and 6 with the line-contacts otl springjacks Z and CZ in the switchboard.

The core of the repeating-coil is provided with an armature b3, whose lever closes upon a contact-point b4 when it is attracted. The levercarrying armature 3 is connected by a conductor 7 with one pole ot' battery c, while the contact-point b* of the relay is connected by a conductor 8 with the other pole of the battery. A resistance-coil e is interposed in conductor 7. A signal-lamp f is included in conductor 8, placed near the spring-jack CZ in the switchboard, so as to be permanently associated with it. Conductor 7 is also connected with the contact-rings g2 of the springjacks by a wire 9, brought from a point between tlie resistance-coil and the lever of the relay.

Two plugs /L and 7L', forming the terminals of a plug-circuit 10 11, are shown at one seetion of the switchboard. In addition to the usual contact-pieces and e, which register with the line-springs g and g of the springjack, there is a sleeve 2 in the plug which connectsy with the thimble g2 of the spring-jack. The two sleeves zot the plugs /L and /t form the terminals of two wires 12 and 13, respectively,which include supervisory signal-lam ps 7n and associated with the corresponding plugs. These conductors are united and connected through a wire 14 with a battery c. The usual calling-key Z is furnished for the use of the operator in signaling to a substation and a listening-key m for connecting her telephone with the plug-circuit. This system of circuits comprises two distinct organizations, both supplied with exciting-current from battery c. One system Vconsists of the line-circut including one helix ot' the relay and controlled at the substation, the design being to cause the excitement of the relay during the use of the substation-teleplione, the secondary circuit including the other helix of the repeating-coil and terminating in the springjacls in the telephone-switchboard and the line-contacts of the plugs and the conductors which unite them for establishing connections between the secondary circuits oi different lines. The other system consists of local circuit connections controlled by the relay for causing the illumination of the line-lamp in response to the excitement of the relay as an initial signal, for extinguishing the line-lamp when connection is made with the line, for temporarily substituting for the line-lamp a supervisory signal-lamp, and for causing the illumination ot' this latter lamp when the telephone is returned to its position ol" disuse. This latter system of circuits forms no part of the present invention, but is made the sublicct of the prior patent mentioned.

As long as the telephone at the substation station A, for example-is not iii use no current circulates in the line conductors 1 2, since the connection between these is interrupted at the substation by the condenser (1, and the switch ai. When the telephone is reniovcd from its switch for use, the switch closes the bridge 4:, which is ot' comparatively low resistance, whereupon a current is created by battery c in the line which magnetizes the core of relay and causes the attraction of armature 0". The local circuit ot battery c is thus closed through conductors 7 8. The current in this circuit illuminates thc lainpj", whereby the initial call is signalized to the attendant. In response to this signal the operator inserts the plug /L into the spring-jack d and depresses the key m, thus bringing her telephone into a closed circuit with the helix b2 otl coil so that she can learn the ordci lor the required connection. A new arrangement of the local circuits is at the same time brought about, a path being t'ormed from battery c through wires 14 and 12 to the sleeve i oi? the plug, thence to the thiiiible (fof the springjack, and thence through wires 9 and 7, returning to battery c. The supervisory lamp is thus brought into parallel circuit with the line-la1up f, both being in series with the resistancecoil e. This coil is of such resistance with relation to that o1: the lamps that the current through it is insuiiicicnt to illuminate both lanipswhen thus placed in parallel. Consequently the line-lamp f is extinguished and the supervisory lamp remains unlighted.

Vheii the number ot' the desired correspondent line B has been obtained, the operator may test the spring-jack of that line in the usual way and, linding the line irce, may insert the plug /t into the spring-jack. She may then signal the required station B by means of the calling-key l. lVhile the liliecircuit at that station remains discontinuous, the relay of the line remains inert, so that the circuit through the line-lamp f, which it controls, is open. Hence thc entire current through wii'e 7 and resistance-coil i ol that line traverses the path 9, 13, `and 11, lighting the supervisory lamp t". The illun'iination ol this lamp then indicates to the operator that the called subscriber has not responded.

When the telephone at the station B is removed from its hook, the repeating-coil relay becomes excited and closes the circuit through its lamp f, thus extinguishing the supervisory lamp 'i. The two lines will then be in inductive connection with each other. Telephonie currents through line-circuit 1 2 to station A will be repeated by the coil in that line into the secondary circuit, made up of conductors 5 6 of each of the lines, and the lOO IIS

plug-circuit 1011, and from this secondary circuit again into thefline-circuit through the medium of the repeating-coil b in the line to station B. y

Whilethe telephones at the siibstations remain in use the supervisory lamps will remain dark; but when both telephones are replaced upon their switch-hooks both relays willA release their armatures, whereby the currents through both line-lamps f will be interrupted, and the entire currents through the coils e will be diverted through the supervisory lamps /c and c, respectively. The simultaneous illumination of these lamps may be taken as a signal for disconnection.

It will be apparent that no action of the operator in making or breaking connection between lines can vary the current in the linecircuits, the latter being dependent wholly on the position of the telephone-s witches at the stations. Henceno disturbance can arise in the telephones through changes in the strength ot' current in the line resulting from altering the circuit connections in the switchboard such as characterize the systems for automatic signaling commonly in use,

I claim as my invention- 1. The combination with a telephone-circuit and means for producing signaling-current in the circuit, of a repeating-coil interposed in the circuit, an armature for the repeating-s coil responsive to the iow of signaling-current therein, a local circuit containing a subsidiary signal and a source of current, switchcontacts operated by the armature of the repeating-coil, controlling said local circuit, a second subsidiary signal in a conductor adapted to form ashunt about the first-mentioned signal and the switch-contacts,'and means for closing said shunt-path, whereby both of said subsidiary signals are rendered responsive at different times, to the ilow of signaling-current in the main telephone-circuit, substanstantially as set forth.

2. rI`he combination with a telephone-line extending-from a substation to a central oiice, of a spring-jack for the line at the central olice, a repeating-coil interposed between the spring-jack and the line, one winding of said repeating-coil being in the line-circuit and the other winding in the portion of the circuit leading to the spring-jack, a source of signaling-current in the main circuit with a switch at the substation for determining the iiow of current in the line, a plug and plug-circuit for making connection with the line at the spring-jack thereof, an armature for the repeating-coil, a subsidiary line-signal in a local circuit, switch-contacts operated by the armature controlling said local circuit, a shuntcircuit about said line-signal, said shunt-circuit being established in making connection with the line, rand a supervisory signal in the shunt-circuit, as described.

ing, a telephone-circuit and a switch for bringing said circuit into connection with the second winding oi' the magnet, whereby said circuits lare united inductively.

4C. In a telephone-exchange system,the combinationwith two lines extending from substation's to a central oiiice, of a repeating-coil for each line at the central oiice, having one of its windings in the line, means for temporarily connecting together the remaining windings of the coils, to imite the two lines telephonically, a source of current permanently connected with each line, anda switch at `each substation controlling the circuit, a relayarmature for the core of each coil, a line-signal for each line in a local circuit controlled vby the relay-armature of the corresponding repeating-coil, a supervisory signal for each line, and alocal circuit for each of said supervisory signals bringing the same under the control ot the corresponding relay-armature, established in connecting the two lines-telephonically through their repeating-coils, substantially as set forth.

'repeating-coil for each line having one winding in the line-circuit, an armature for the core ot each repeating-coil, a subsidiary line- IOO.

signal foreach line in alocal circuit controlled bythe armature of the corresponding repeatv ing-coil relay, means for uniting the remaining windings of the two repeating-coils, two subsidiary supervisory signals, and means for temporarily associating. each of the signals with one of the said local circuits to be controlled by the saidA repeating-coil relay, when connection is made between the said windings, substantially as described. y

6. In combination, two telephone-lines,each having at its substation a telephone-switch for closing the line-circuit, a source of current in each line-circuit, a repeating-coil for each line having one of its windings in the line-circuit, and having its other winding connected with a spring-jack in a switchboard, an armature controlled by the core of each repeating-coil, a subsidiary line-signal in a local circuit with a source of current controlled by the armature of the corresponding repeating-coil, a plug-circuit for uniting diferent spring-jacks, a supervisory signal associated with each plug and circuit connections closed in the act of putting a plug into a spring-jack adapted vto bring the corresponding supervisory signal' Iinto a circuit controlledby the relay of the IZO line with which the plug is connected and to shunt the linesignal, substantially as described.

7. The combination with a telephone-line, a battery permanently connected with the line at the central office, a switch determining the flow of current in the line operated in the use of the telephone, and a repeating-coil interposed in the line-circuit, of relay-contacts controlled by the repeating-coil, a socket for the line and a plug and plug-circuit therefor, a supervisory signal associated with the plugcircuit, and circuit connections closed in mal;- ing connection with the line adapted to bring the signal under the control ot' the repeatcoil relay, the supervisory signal being thereafter responsive to the movements o't the relay-armature produced by the flow of signaling-current in the line, as described.

8. In a central-battery telephone system, the combination with telephone-lines extending from substations and permanently connected at the central oHice to the poles of a central battery, of a substation-telephone switch for each line controlling the iow or' current therein, a repeating-coil magnet for each line having a winding connected in the line-circuit and an independent Winding in inductive relation to said Erst-mentioned winding, link conductors at the central oiliee, and connection-switches adapted to establish a local cir- Y cuit through said link conductors including' the independent windings of the magnets of two lines, whereby the said two lines are united telephonically, an armature for the repeating-coil magnet or' each line, and signal apparatus responsive to the movements of said armature to indicate the open or. closed condition of the telephone-switch at the corresponding substation,substantially as set forth.

9. In combination, two telephone-lines eX- tending from substations to a central oiice, a battery permanently connected with both lines, and a switch at the substation of each line for controlling the flow of current therein, a repeating induction-coil 'lor each line having one of its windings included directly in the line-circuit, an armature lor each repeating-coil controlling` a local circuitcon taining a subsidiary signal, and means for switchingI the remaining windings of the repeatingcoils together,to form an intermediate switchboard-circuit, and to constitute a talking-circuit composed ot' three inductivelv -united sections between the substations o1 said lines, the said talking-circuit having a source ol steady current in each oi its two end or line sections, but not in the central or switchboard section, the signals controlled by the batterycurrent being responsive imlepcndently each to current in its own line, substantially as set forth.

lO. The combination with a telephone-line extending from a substation to a central olliee, or' a source ot' current and means at the suhstation for determining the ilow oi current in the line, a repeating-coil at the central oiliec having one winding included in the line-cil'- cuit and another winding independent thereof, a spring-jack for the line, a plug` lor inaking connection therewith, and a switchboardcircuit, established in registering contacts otl the plug and spring-jack, including the second-mentioned winding` of the repeating-coil, an armature for the repeating-coil, a local circuit including a subsidiary line-signal coutrolled by said armature, the line-signal hcing responsive to the movcnient ol said armature, a supervisory signal and a circuit iucluding the same, established in makingl counection with the spring-jack ol the telephoneline,said last-mentioned circuit being` in shunt of the subsidiary line-signal, as described.

In witness whereof I hereunto subscribe my name this 2d day otl October, A. l). 1399.

CHARLES IC. SUHIBNICH.

IVitnesses:

ELLA EDLER, FLORENCE E. Sommes. 

